Karl Trygve Kalleberg

Age Labs

Objectives We aimed to describe the trajectories of cognitive and physical symptoms before, during, and after a positive- or negative SARS-CoV-2 test and in untested controls. Design A prospective cohort study. Setting Norway, 27 March 2020 to 6 July 2022 Participants A total of 146 065 volunteers were recruited. Of these, 120 605 participants (mea...

Background COVID-19 is primarily known as a respiratory illness; however, many patients present to hospital without respiratory symptoms. The association between non-respiratory presentations of COVID-19 and outcomes remains unclear. We investigated risk factors and clinical outcomes in patients with no respiratory symptoms (NRS) and respiratory sy...

Ageing is a heterogeneous multisystem process involving different rates of decline in physiological integrity across biological systems. The current study dissects the unique and common variance across body and brain health indicators and parses inter‐individual heterogeneity in the multisystem ageing process. Using machine‐learning regression mode...

Importance Research diversity and representativeness are paramount in building trust, generating valid biomedical knowledge, and possibly in implementing clinical guidelines. Objectives To compare variations over time and across World Health Organization (WHO) geographic regions of corticosteroid use for treatment of severe COVID-19; secondary obj...

Ageing is a heterogeneous multisystem process involving different rates of decline in physiological integrity across biological systems. The current study dissects the unique and common variance across body and brain health indicators and parses inter-individual heterogeneity in the multisystem ageing process. Using machine-learning regression mode...

Objective To determine if daily supplementation with cod liver oil, a low dose vitamin D supplement, in winter, prevents SARS-CoV-2 infection, serious covid-19, or other acute respiratory infections in adults in Norway. Design Quadruple blinded, randomised placebo controlled trial. Setting Norway, 10 November 2020 to 2 June 2021. Participants 34...

Although substantial progress has been made in managing COVID-19, it is still difficult to predict a patient’s prognosis. We explored the epigenetic signatures of COVID-19 in peripheral blood using data from an ongoing prospective observational study of COVID-19 called the Norwegian Corona Cohort Study. A series of EWASs were performed to compare t...

The International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) COVID-19 dataset is one of the largest international databases of prospectively collected clinical data on people hospitalized with COVID-19. This dataset was compiled during the COVID-19 pandemic by a network of hospitals that collect data using the ISARIC-World...

Background For many people public transport is the only mode of travel, and it can be challenging to keep the necessary distances in such a restricted space. The exact role of public transportation and risk of SARS-CoV-2 transmission is not known. Methods Participants (n = 121,374) were untested adult Norwegian residents recruited through social m...

Rationale & Objective Studies published from countries with a high prevalence of COVID-19 have found increased incidence and a more severe disease course of COVID-19 in kidney transplant recipients than in the general population. We investigated how the first wave of the COVID-19 pandemic affected the everyday life of kidney transplant recipients i...

Background: For many people public transport is the only mode of travel, and it can be challenging to keep the necessary distances in such a restricted space. The exact role of public transportation and risk of SARS-CoV-2 transmission is not known. Methods: Participants (n=121 374) were untested adult Norwegian residents recruited through social me...

Long-COVID-19 is a proposed syndrome negatively affecting the health of COVID-19 patients. We present data on self-rated health three to eight months after laboratory confirmed COVID-19 disease compared to a control group of SARS-CoV-2 negative patients. We followed a cohort of 8786 non-hospitalized patients who were invited after SARS-CoV-2 testin...

Ten years ago, we published the article Finding software license violations through binary code clone detection at the MSR 2011 conference. Our paper was motivated by the tendency of em- bedded hardware vendors to only release binary blobs of their rmware, often violating the licensing terms of open-source soft- ware present inside those blobs. The...

This cohort study examines self-reported memory problems 8 months after COVID-19 infection.

Background: Neurological manifestations of COVID-19 range from ageusia and anosmia, experienced by most patients, to altered consciousness and rare and severe encephalopathy. A direct affection of the central nervous system (CNS) in the disease has been supported by animal models and MRI findings in patients with mild and severe symptoms. Here we r...

Background The risk factors for SARS-CoV-2 transmission are not well characterised. We sought to identify potential risk factors for transmission and actionable information that can be used to prevent SARS-CoV-2. Methods Individuals tested for SARS-CoV-2 at four accredited laboratories were invited. In addition, participants were recruited through...

Background The risk factors for SARS-CoV-2 transmission are not well characterised in Western populations. We sought to identify potential risk factors for transmission and actionable information to prevent for SARS-CoV-2. Methods Individuals tested for SARS-CoV-2 at four major laboratories were invited. In addition, participants were sampled by c...

Importance Mammography screening currently relies on subjective human interpretation. Artificial intelligence (AI) advances could be used to increase mammography screening accuracy by reducing missed cancers and false positives. Objective To evaluate whether AI can overcome human mammography interpretation limitations with a rigorous, unbiased eva...

Software is rapidly moving from the desktop to the Web. The Web provides a generic user interface that allows ubiquitous access, instant collaboration, integration with other online services, and avoids installation and configuration on desktop computers. For software development, the Web presents a shift away from developer workstations as a silo,...

Software released in binary form frequently uses third-party packages without respecting their licensing terms. For instance, many consumer devices have firmware containing the Linux kernel, without the suppliers following the requirements of the GNU General Public License. Such license violations are often accidental, e.g., when vendors receive bi...

In meta-programming with concrete object syntax, meta programs can be written using the concrete syntax of manipulated programs. Quotations of concrete syntax fragments and anti-quotations for meta-level expressions and variables are used to manipulate the abstract representation of programs. These small, isolated fragments are often ambiguous and...

Modern IDEs increase developer productivity by incorporating many different kinds of editor services. These can be purely syntactic, such as syntax highlighting, code folding, and an outline for navigation; or they can be based on the language semantics, such as in-line type error reporting and resolving identifier declarations. Building all these...

This paper presents the main results and conclusions of the Third Rewrite Engines Competition (REC III). This edition of the competition took place as part of the 8th Workshop on Rewriting Logic and its Applications (WRLA 2010), and the systems ASF+SDF, Maude, Stratego/XT, Tom, and TXL participated in it.

The Second Rewrite Engines Competition (REC) was celebrated as part of the 7th Workshop on Rewriting Logic and its Applications (WRLA 2008). In this edition of the competition participated five systems, namely ASF+SDF, Maude, Stratego/XT, TermWare, and Tom. We explain here how the competition was organized and conducted, and present its main result...

Testing and instrumenting software are among the foremost techniques for ensuring software reliability. We present ongoing work on two Eclipse extensions that try to make the use of axioms and data invariants as convenient a part of the development process as unit tests.

EventScript is a simple but powerful language for programming reactive processes. A stream of incoming events is matched against a regular expression. Actions embedded within the regular expression are executed in response to the matching of patterns of events. These actions include assigning computed values to vari- ables and emitting output event...

EventScript is a simple but powerful language for programming reactive processes. A stream of incoming events is matched against a regular expression. Actions embedded within the regular expression are executed in response to the matching of patterns of events. These actions include assigning computed values to variables and emitting output events....

Stratego/XT is a language and toolset for program transformation. The Stratego language provides rewrite rules for expressing basic transformations, programmable rewriting strategies for controlling the application of rules, concrete syntax for expressing the patterns of rules in the syntax of the object language, and dynamic rewrite rules for expr...

Program transformation systems provide powerful analysis and transformation frameworks as well as concise languages for language processing, but instantiating them for every subject language is an arduous task, most often resulting in half-completed frontends. Compilers provide mature frontends with robust parsers and type checkers, but solving lan...

Dealing with failure and exceptional situations is an important but tricky part of programming, especially when reusing existing components. Traditionally, it has been up to the designer of a library to decide whether to use a language's exception mechanism, return values, or other ways to indicate exceptional circumstances. The library user has be...

Programming languages have a dual role in the construction of software. The language is both our substrate (the stuff we make software from), and our tool (what we use to construct software). Program transformation (PT) deals with the analysis, manipulation and generation of software. Therefore a close relationship exists between program transforma...

Properties such as logging, persistence, debugging, tracing, distribution, performance monitoring and exception handling occur in most programming paradigms and are normally very difficult or even impossible to modularize with traditional modularization mechanisms because they are cross-cutting. Recently, aspect-oriented programming has enjoyed rec...

Stratego/XT is a language and toolset for program transformation. The Stratego language provides rewrite rules for expressing basic transformations, programmable rewriting strategies for controlling the application of rules, concrete syntax for expressing the pat- terns of rules in the syntax of the object language, and dynamic rewrite rules for ex...

Feature modeling has been proposed as an approach for describing variable requirements for software product lines. In this paper, we explore the relationship between feature models and ontologies. First, we examine how pre- vious extensions to basic feature modeling move it closer to richer formalisms for specifying ontologies such as MOF and OWL....

Some transformations and many analyses on programs are either dif- ficult or unnatural to express using terms. In particular, an alyses that involve type contexts, call- or control flow graphs are not easily capture d in term rewriting systems. In this paper, we describe an extension to the System S term rewriting system that adds references. We sh...

By now, the concept of program slicing has been known in the research community for around 25 years. As a research topic, it has enjoyed a fair share of popularity, evidenced by the number of articles published on the topic following Mark Weiser's seminal paper. However, outside research circles, program slicing appears to be virtually unknown. In...

The use of a high-level, abstract coding style can greatly increase developer productivity. For numerical software, this can result in drastically reduced run-time performance. High-level, domain-specific optimisations can eliminate much of the overhead caused by an abstract coding style, but current compilers have poor support for domain-specific...

The use of a high-level, abstract coding style can greatly increase developer productivity. For numerical software, this can result in drastically reduced run-time performance. High-level, domain-specific optimisations can eliminate much of the overhead caused by an abstract coding style, but current compilers have poor support for domain-specific...

Recently, aspect-oriented programming has enjoyed recognition as a practical solu-tion for an important class of separate and cross-cutting concerns. This paper shows aspects to be useful in the context of rule-based programming languages by demon-strating an adaptable term type checker and after-the-fact algorithm extension. It briefly discusses s...

Domain-specific languages (DSLs) can greatly ease program development compared to general-purpose languages, but the cost of implementing a domain-specific language can be prohibitively high compared to the perceived benefit. This is more pronounced for narrower domains, and perhaps most acute for domain-specific aspect languages (DSALs). A common...

Abstract Integrated Development Environments (IDEs) increase productivity by providing a rich user interface and rapid feedback for a specific language. Creating an editor for a specific language is not a trivial undertaking, and is a cumbersome,task even when working with an extensible framework,such as Eclipse. A new IBM- guided eort, the IMP fra...

Effective code reuse is desirable, but difficult to achieve in practice, since it is often necessary to adapt code before it can be reused successfully. The good old solution to code reuse is simple: copy, paste, then edit as needed. This is a brilliant idea, except for the maintenance problems it causes. In this paper we introduce a language exten...